Apes Have Midlife Crises

Below:

Next story in Science

Across many cultures, people report a dip in happiness during
their late-40s, a time when they generally feel less satisfied
with their lives than they do in their younger and older years.

Apes, too, experience a kind of midlife crisis, found a new
study. The surprising result suggests that the middle-aged blues
may be a result of biology, not culture, and its evolutionary
roots run deep.

"It was an astounding thing for us to find this pattern, to be
honest," said Andrew Oswald, an economist and behavioral
scientist at the University of Warwick in the United Kingdom. "It
may be that the midlife crisis is driven by primate biology in a
way we don 't understand, and if that 's the case, we all have to
learn how to deal with it."

"I think it 's helpful for people to understand this dip," he
added. "With luck, this could people them see that this is
completely normal and that could help them get through it."

Studies in more than 50 countries over the past 20 years have
revealed a near-universal pattern. Over the course of life,
happiness tends to follow a U-shaped curve, with people ranking
their sense of well-being higher in the first and last decades of
life than in the middle.

The low point generally strikes between age 45 and 50 for both
men and women, and the pattern crosses economic and demographic
lines.

Most theories for the midlife dip involve money, promotions,
marriage and other social facets of modern life, Oswald said. To
see if there might be another explanation, he and colleagues
compiled data that had been collected on more than 500 orangutans
and chimpanzees living in about 60 zoos around the world.

For each animal, zookeepers, researchers or caretakers answered
four questions about the well-being of their primate friends,
including whether the apes seemed to be in good or bad moods. The
humans also ranked how happy they thought they 'd be if they were
to become the animal for a week. They had spent time with the
animals for at least two years and knew them well.

Apes live to be about 50 or 55 years old and, just like in
people, results showed a drop in happiness that reached its
lowest point about halfway through the animals ' lives, the
researchers report today in the journal Proceedings of the
National Academy of Sciences.

The magnitude of the dip was on par with the dips in happiness
that people experience in their middle age, Oswald said. He
compared the difference between the apes ' highs and lows to the
loss in well-being that people report with marital separation.

The new findings help rule out some theories for midlife slumps
in humans, said Arthur Stone, a psychologist in the psychiatry
department at Stony Brook University in New York. For example, a
whole generation of people can end up feeling less happy at a
certain time in their lives simply because of some external
historical situation. But that is unlikely to happen in societies
of apes.

Instead, it might be chemical or physical changes in our bodies
that influence how our feelings morph throughout our lifetimes.

"What this really starts to point to is that maybe there are
biological things that we just don 't know about," Stone said.
"Maybe there are changes in the brain, changes in how
neurotransmitters work or changes in how hormones work that
relate to how people view their lives and how animals feel.
People will be looking at this more seriously, I think."